Treatment of children with poor risk solid tumors by further escalation of the VETOPEC regimen including very high-dose cyclophosphamide and peripheral stem cell support: an Australian and New Zealand Children's Hematology and Oncology Group study

Impact of cyclophosphamide on the morphological and histological changes in polyglycolic acid spacers

In radiotherapy for pediatric abdominal tumors, determining the effect of concurrent chemotherapy on polyglycolic acid (PGA) spacers is crucial; yet this effect has not been validated. Therefore, we aimed to evaluate the impact of cyclophosphamide (CPA) chemotherapy on the PGA spacer using a rat model. Twenty-four rats were implanted with the spacer, and morphological changes in the spacer were assessed on CT for both the CPA-dosed group (40 mg/kg) and the control group. The size and volume of the spacer were quantified using CT, while the degree of adhesion and microscopic examination of the tissue were determined using pathology specimens. Morphologically, the size of the spacer decreased over time in both the CPA-dosed and control groups, with no significant differences observed between groups. No significant differences in adhesion were observed between the two groups. Macrophages were observed around the PGA fibers, suggesting their involvement in the degradation of the PGA spacer. These results suggest that CPA does not cause significant clinically problematic degradation or adverse tissue reactions to the PGA spacer. This study reinforced the benefits of PGA spacers; however, future research focusing on in vivo longitudinal monitoring of individual rats, as well as on humans, is required.

Association between CYP2B6 genetic variability and cyclophosphamide therapy in pediatric patients with neuroblastoma

Cyclophosphamide, an oxazaphosphorine prodrug is frequently used in treatment of neuroblastoma, which is one of the most prevalent solid organ malignancies in infants and young children. Cytochrome P450 2B6 (CYP2B6) is the major catalyst and CYP2C19 is the minor enzyme in bioactivation and inactivation pathways of cyclophosphamide. CYP-mediated metabolism may contribute to the variable pharmacokinetics of cyclophosphamide and its toxic byproducts leading to insufficient response to the therapy and development of clinically significant side effects. The aim of the study was to reveal the contribution of pharmacogenetic variability in CYP2B6 and CYP2C19 to the treatment efficacy and cyclophosphamide-induced side effects in pediatric neuroblastoma patients under cyclophosphamide therapy (N = 50). Cyclophosphamide-induced hematologic toxicities were pivotal in all patients, whereas only moderate hepatorenal toxicity was developed. The patients' CYP2B6 metabolizer phenotypes were associated with the occurrence of lymphopenia, thrombocytopenia, and monocytopenia as well as of liver injury, but not with kidney or urinary bladder (hemorrhagic cystitis) toxicities. Furthermore, the patients' age (< 1.5 years, P = 0.03) and female gender (P ≤ 0.02), but not CYP2B6 or CYP2C19 metabolizer phenotypes appeared as significant prognostic factors in treatment outcomes. Our results may contribute to a better understanding of the impact of CYP2B6 variability on cyclophosphamide-induced side effects.

The role of SIOP as a platform for communication in the global response to childhood cancer

Since the year 2000, there has been a 35% annual decrease in mortality among children under the age of five worldwide. The decrease is mainly attributed to the decrease in childhood epidemic infections, for example, due to vaccination programs. In the near future, this decrease will draw attention to paediatric non-communicable diseases (NCDs), and cancer is one of the most common. Access to care for children with cancer and survival rates have improved dramatically in high-income countries. However, it is important that a global perspective addresses problems in developing countries in particular. To meet this challenge, it is critical that emphasis is placed on demands such as access to care and drugs that are known to be effective, and which can be safely administered in resource-limited settings. Additionally, cancer registries and improved health care structures that include care for children with cancer, are paramount for further progress to increase awareness and the survival of children with cancer. The purpose of this paper is to describe current worldwide interventions to improve childhood cancer from the perspective of the International Society of Paediatric Oncology (SIOP). This global perspective will serve as an introduction to a series of papers from six SIOP continental branches, which will highlight the specific and/or common issues related to children with cancer worldwide. To strengthen the communication among and synergistic effects of various paediatric cancer stakeholders, SIOP could serve as a global platform for a proposed Global Paediatric Cancer Network through the interaction of its continental branches and partner collaborations.